kubectl-sql

kubectl-sql is a kubectl plugin that use SQL like language to query the Kubernetes cluster manager

• Install
• What can I do with it ?
• Alternatives

More docs

• kubectl-sql's query language
• More kubectl-sql examples
• Using the config file

Install

Using krew plugin manager to install:

kubectl krew install sql
kubectl sql --help

Using Fedora Copr:

dnf copr enable yaacov/kubesql
dnf install kubectl-sql

From source:

git clone git@github.com:yaacov/kubectl-sql.git
cd kubectl-sql

make

What can I do with it ?

kubectl-sql let you select Kubernetes resources based on the value of one or more resource fields, using human readable easy to use SQL like query language. It is also posible to find connected resources useing the join command.

More kubectl-sql examples

# Get all pods from current namespace scope, that has a name starting with "virt-" and
# IP that ends with ".84"
kubectl-sql get pods where "name ~= '^virt-' and status.podIP ~= '[.]84$'"
AMESPACE	NAME                          	PHASE  	hostIP        	CREATION_TIME(RFC3339)       	
default  	virt-launcher-test-bdw2p-lcrwx	Running	192.168.126.56	2020-02-12T14:14:01+02:00
...

# Get all persistant volume clames that are less then 20Gi, and output as json.
kubectl-sql -o json get pvc where "spec.resources.requests.storage < 20Gi"
...

# Display non running pods by nodes for all namespaces.
kubectl-sql join nodes,pods on \
    "nodes.status.addresses.1.address = pods.status.hostIP and not pods.phase ~= 'Running'" -A
...

# Filter replica sets with less ready-replicas then replicas"
kubectl-sql --all-namespaces get rs where "status.readyReplicas < status.replicas"

Output formats:

--output flag	Print format
table	Table
name	Names only
yaml	YAML
json	JSON

Alternatives

jq

jq is a lightweight and flexible command-line JSON processor. It is possible to pipe the kubectl command output into the jq command to create complicated searches ( Illustrated jq toturial )

https://stedolan.github.io/jq/manual/#select(boolean_expression)

kubectl --field-selector

Field selectors let you select Kubernetes resources based on the value of one or more resource fields. Here are some examples of field selector queries.

https://kubernetes.io/docs/concepts/overview/working-with-objects/field-selectors/